• Bacterial Infection
• COPD Pathology

Bacterial colonisation/infection is ubiquitous in patients with COPD and is likely a biologically relevant facet of disease progression. Correlations have been reported between the identification of bacteria and increases in the intensity of the inflammatory/immune response, cough, sputum production and rates of acute exacerbations of COPD.1–5 The inflammatory/immune response in COPD also persists despite smoking cessation and there is a particularly enhanced inflammatory response in chronic bronchitis and acute exacerbations of COPD, all of which is consistent with a microbial mechanism underlying chronicity and exacerbations. Chronic bacterial colonisation in COPD subjects had been traditionally evaluated by cultivation-based methods of sputum and bronchoalveolar lavage (BAL), with the magnitude and types of organisms varying widely. Culture-independent analyses, such as those used in the study by Einarsson et al,6 are providing new insights into the pulmonary microbiome of patients with COPD. This current study underscores the concept that the COPD lung harbours a microbiome distinct from that in healthy non-smokers and smokers, which is not captured completely by standard culture techniques. Overall, this study, together with complementary studies from other labs,6–13 is building a ‘research mosaic’ that is identifying the changes in the microbiome that occur during COPD and delineating their importance in the pathogenesis of the disease.

In the paper by Einarsson et al,6 the objective was to determine whether there are …